Behentrimonium

Behentrimonium refers to a family of quaternary ammonium salts derived from behenic acid, with behentrimonium chloride being the most common form used in cosmetics. It is a cationic conditioning surfactant widely employed in hair care and, to a lesser extent, skin care products. The long-behenyl alkyl chain provides conditioning and slip, while the quaternary ammonium center carries a positive charge that facilitates binding to negatively charged surfaces such as hair cuticles and skin keratin. This binding helps to smooth the hair surface, reduce static, improve detangling, and impart a soft, conditioned feel.

In formulations, behentrimonium chloride is typically used in shampoos, conditioners, leave-in treatments, and some styling products. It is usually applied at low concentrations in rinse-off products and can be included at higher levels in leave-on products, depending on the product type and regulatory limits. The ingredient is often supplied as an oil-based derivative with a defined active matter percentage, and formulators select the counterion (chloride, sulfate, or others) to suit formulation behavior, compatibility, and stability.

Safety and regulation: Behentrimonium chloride is a widely used cosmetic ingredient and is generally considered safe for topical use within approved concentration ranges. Some individuals may experience mild skin or eye irritation, especially at higher concentrations. As with other quaternary ammonium compounds, compatibility with certain anionic ingredients can influence stability and performance in a formula.

See also: quaternary ammonium compound, hair conditioning agents, cosmetic ingredient.